Adverbs from Adjectives and Comparison | Icelandic Grammar

English builds most manner adverbs with one tidy suffix: quick → quickly, natural → naturally, bad → badly. Icelandic has two main routes, and which one a given adjective takes is partly a matter of class and partly something you learn word by word. The first route is to use the neuter form of the adjective as the adverb (fljótt — "fast / quickly"); the second is the suffix -lega (eðlilega — "naturally"). On top of that, these adverbs compare — fljótt → fljótar → fljótast ("fast → faster → fastest") — and a small cluster of the most common adverbs compare irregularly (vel → betur → best). This page covers how manner adverbs are derived and compared. (The basic fact that the neuter adjective can do adverbial duty is assumed; here we focus on derivation patterns and comparison.)

Route 1: the adverb IS the neuter adjective

For a large group of adjectives, the manner adverb is identical to the neuter singular strong form of the adjective. You already know that form from adjective agreement; you just reuse it adverbially. So fljótur ("fast," masc.) has neuter fljótt, and that same fljótt is the adverb "quickly":

Hann talar mjög fljótt — ég næ ekki öllu.

He talks very fast — I can't catch everything. (fljótt = neuter of fljótur, used as adverb)

Krakkarnir borðuðu hratt og hlupu út.

The kids ate quickly and ran outside. (hratt = neuter of hraður 'fast', used adverbially)

Hún syngur fallega.

She sings beautifully. (fallega — here from fallegur)

A small wrinkle worth flagging honestly: the neuter ending is usually -t (fljótt, gott → "well/good"), but a handful of adverbs end in -a rather than -t (illa — "badly," lengi — "for a long time"). You cannot always derive the exact shape mechanically, so treat the common manner adverbs as vocabulary items, confirming the form as you learn each one.

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For many adjectives the manner adverb is simply the neuter form: fljótur → fljótt ("quickly"), góður → vel/gott. The ending is usually -t, but a few take -a (illa, lengi). Learn the high-frequency ones as set words rather than deriving them on the fly.

Route 2: the -lega suffix

A second large class forms adverbs with the suffix -lega, attached to the adjective stem. This is the closest analogue to English -ly, and it is especially common with longer, more abstract adjectives and with sentence adverbs (the "naturally, probably, especially" type).

Venjulega fer ég að sofa um ellefu.

I usually go to bed around eleven. (venjulega, from venjulegur 'usual')

Hún kemur líklega seinna í kvöld.

She'll probably come later tonight. (líklega, from líklegur 'likely')

Þetta er sérstaklega mikilvægt.

This is especially important. (sérstaklega, from sérstakur 'special')

Auðvitað talar hann eðlilega um þetta.

Of course he talks about this naturally / matter-of-factly. (eðlilega, from eðlilegur 'natural')

Notice that several -lega adverbs are sentence adverbs — venjulega ("usually"), líklega ("probably"), vonandi-type commentary — rather than pure manner adverbs. The -lega suffix is your reliable signal that a word is functioning adverbially; when you coin or recognise a new adverb from an abstract adjective, -lega is usually the right tool.

Comparison: -ar for the comparative, -ast for the superlative

Just like adjectives, manner adverbs have three degrees: positive → comparative → superlative. The regular pattern adds -ar for the comparative and -ast for the superlative. Importantly, unlike adjectives, comparative and superlative adverbs do not inflect for gender, number, or case — they are fixed forms, which is a small mercy.

Positive	Comparative (-ar)	Superlative (-ast)	Meaning
fljótt	fljótar	fljótast	fast → faster → fastest
oft	oftar	oftast	often → more often → most often
hægt	hægar	hægast	slowly → more slowly → most slowly
sjaldan	sjaldnar	sjaldnast	seldom → more seldom → most seldom

Geturðu talað aðeins hægar?

Could you speak a bit more slowly? (hægar = comparative of hægt)

Ég fer oftar í sund á sumrin.

I go swimming more often in the summer. (oftar = comparative of oft)

Hann hleypur hraðast í bekknum.

He runs the fastest in the class. (hraðast = superlative)

The key English-to-Icelandic adjustment: English uses more / most for longer adverbs ("more slowly," "most often"), but Icelandic strongly prefers the synthetic -ar / -ast forms — hægar, not meira hægt; oftast, not mest oft. Reaching for meira + adverb where a synthetic comparative exists is one of the most common learner tells.

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Icelandic compares adverbs synthetically: add -ar (comparative) and -ast (superlative) — fljótar, oftast — rather than using "more/most." Don't say meira hægt for "more slowly"; say hægar. And unlike adjectives, these adverb forms don't change for gender or case.

The irregular set — memorise these as a block

A small group of the most frequent adverbs compares irregularly, with suppletive forms (a different root in the comparative/superlative). Because these are exactly the words you use constantly — "well," "badly," "much," "long" — you must know them cold. The good news is that there are only a handful, so learning them as a memorised block pays off immediately.

Positive	Comparative	Superlative	Meaning
vel	betur	best	well → better → best
illa	verr	verst	badly → worse → worst
mikið	meira	mest	much → more → most
lítið	minna	minnst	little → less → least
lengi	lengur	lengst	(for) long → longer → longest
gjarnan	heldur	helst	gladly → rather → most of all / preferably

Mér líður miklu betur í dag, takk.

I feel much better today, thanks. (betur = irregular comparative of vel)

Þetta gekk verr en ég bjóst við.

That went worse than I expected. (verr = irregular comparative of illa)

Ég vil helst fara snemma heim.

I'd most prefer to go home early. (helst — the superlative in the gjarnan/heldur/helst set)

Hún hefur búið hér lengst af öllum.

She has lived here the longest of everyone. (lengst = superlative of lengi)

These map directly onto the English irregulars — well/better/best, badly/worse/worst, much/more/most are suppletive in English too — so the idea is familiar; only the forms are new. The trap is half-knowing them and producing a hybrid like meira vel ("more well") instead of betur. Treat vel/betur/best and illa/verr/verst as indivisible chains.

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The irregular adverb comparatives — vel/betur/best, illa/verr/verst, mikið/meira/mest, lítið/minna/minnst, lengi/lengur/lengst — are high-frequency. Memorise them as fixed three-step chains. Never build a regular or "more"-style form from them (no meira vel, no vel-ar).

Common Mistakes

❌ Geturðu talað meira hægt?

Incorrect — Icelandic uses the synthetic comparative hægar, not meira + adverb.

✅ Geturðu talað hægar?

Could you speak more slowly? (synthetic comparative hægar)

Using meira + adverb where a synthetic -ar form exists. Say hægar, not meira hægt.

❌ Mér líður meira vel í dag.

Incorrect — vel is irregular; 'better' is betur, not a 'more'-form.

✅ Mér líður betur í dag.

I feel better today. (irregular comparative betur)

Building a "more well" form. vel has the suppletive comparative betur.

❌ Þetta gekk illar en ég bjóst við.

Incorrect — illa is irregular; the comparative is verr, not a regular -ar form.

✅ Þetta gekk verr en ég bjóst við.

That went worse than I expected. (irregular verr)

Forcing the regular -ar ending onto an irregular adverb. illa's comparative is verr.

❌ Hann talar mjög fljót.

Incorrect — the manner adverb is the neuter form fljótt (with -t), not the masculine fljót-.

✅ Hann talar mjög fljótt.

He talks very fast. (neuter-form adverb fljótt)

Using the wrong adjective form as the adverb. The manner adverb is the neuter fljótt, not a masculine/feminine form.

❌ Hún kemur líkleg seinna.

Incorrect — the adverb is líklega (-lega), not the bare adjective líkleg.

✅ Hún kemur líklega seinna.

She'll probably come later. (adverb líklega with -lega)

Dropping the -lega suffix and leaving a bare adjective where an adverb is needed.

Key Takeaways

Manner adverbs come from adjectives by two routes: the neuter form (fljótt, ending usually -t, a few in -a like illa) and the suffix -lega (venjulega, líklega, sérstaklega).
-lega is the productive, -ly-like suffix, common with abstract adjectives and sentence adverbs.
Adverbs compare synthetically: -ar (comparative), -ast (superlative) — fljótar, oftast — and these forms do not inflect for gender, number, or case. Don't use meira/mest where a synthetic form exists.
A short, high-frequency set is irregular and must be memorised as fixed chains: vel/betur/best, illa/verr/verst, mikið/meira/mest, lítið/minna/minnst, lengi/lengur/lengst.
Never blend the two systems — no meira vel, no illar. The irregulars are indivisible.

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